// page 705 两个线程的轮流执行
//: concurrency/waxomatic/WaxOMatic.java
// Basic task cooperation.
package thinkingInJava.concurrency;

import java.util.concurrent.*;
import static thinkingInJava.YTool.YPrint.*;

class Car {
	private boolean waxOn = false;
	public synchronized void waxed() {
		waxOn = true; // Ready to buff
		System.out.println("waxed before notifyAll");
		notifyAll();
		System.out.println("waxed after notifyAll");
		// 虽然其它 wait 线程此时已被唤醒，但当前的锁并要过了这个大括号才会释放
		// 因此仍然要出了这个大括号才能轮到另外一个线程 wait 之后的代码
	}
	public synchronized void buffed() {
		waxOn = false; // Ready for another coat of wax
		notifyAll();
	}
	public synchronized void waitForWaxing()
			throws InterruptedException {
		while(waxOn == false)
			wait();
	}
	public synchronized void waitForBuffing()
			throws InterruptedException {
		while(waxOn == true)
			wait();
	}
}

class WaxOn implements Runnable {
	private Car car;
	public WaxOn(Car c) { car = c; }
	public void run() {
		try {
			while(!Thread.interrupted()) {
				printnb("Wax On! ");
				TimeUnit.MILLISECONDS.sleep(200);
				car.waxed();
				car.waitForBuffing();
			}
		} catch(InterruptedException e) {
			print("Exiting via interrupt");
		}
		print("Ending Wax On task");
	}
}

class WaxOff implements Runnable {
	private Car car;
	public WaxOff(Car c) { car = c; }
	public void run() {
		try {
			while(!Thread.interrupted()) {
				car.waitForWaxing();
				printnb("Wax Off! ");
				TimeUnit.MILLISECONDS.sleep(200);
				car.buffed();
			}
		} catch(InterruptedException e) {
			print("Exiting via interrupt");
		}
		print("Ending Wax Off task");
	}
}

public class WaxOMatic {
	public static void main(String[] args) throws Exception {
		Car car = new Car();
		ExecutorService exec = Executors.newCachedThreadPool();
		exec.execute(new WaxOff(car));
		exec.execute(new WaxOn(car));
		TimeUnit.SECONDS.sleep(5); // Run for a while...
		exec.shutdownNow(); // Interrupt all tasks
	}
} /* Output: (95% match)
Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Wax Off! Wax On! Exiting via interrupt
Ending Wax On task
Exiting via interrupt
Ending Wax Off task
 *///:~
